In defining an OCR form for having a character recognition program recognize a new formatted OCR form, it should be conventionally required to measure the size of the form, the relative positions and sizes of page marks, position correction marks (also called a timing or reference mark), character fields, characters with a scale and to input their values. However, the definition of OCR forms is troublesome for programmers. For example, it takes an enormous amount of time to design new dropout OCR forms (a form specially prepared for OCR, and printed with characters and character frames in colors that are not sensed by scanners).
To solve such problems, several conventional techniques have been proposed. As an example, "WinReader Hand, v. 1.5, Users' Manual, Setting of Fields," pp. 19 and 20, Media Drive Co. ("WinReader Hand" is a trademark of Media Drive Co.) describes an approach in which the image of an unfilled form with black frames is captured by a scanner and displayed on a display. All black vertical and horizontal lines are automatically detected and character recognition fields are set after the operator confirms that all rectilinear lines are properly detected.
The above approach requires less tasks by the programmer than the approach using a scale and has much simpler field definitions. The conventional character recognition program described above detects all rectilinear lines to specify fields to which attributes are set and then defines the position and size of the fields to be set with the attributes by using one of the following approaches:
1. Click inside of a ladder frame subject to setting (inside of any one of a plurality of character frames). In this case, all continuing character frames are defined and a part of the ladder frame cannot be defined as a field. PA1 2. Click the upper left corner of the ladder frame subject to setting (a ladder like object consisting of a plurality of continuing character frames) with a mouse, drag it to the lower right corner and release the mouse button. In this case also, all continuing character frames are defined as a field and a part of the ladder frame cannot be defined. PA1 3. Click inside any one character frame contained in a ladder frame subject to setting with the mouse, drag it to the inside of another character frame contained in the ladder frame and release the mouse button. This operation can define a part of the ladder frame as a field.
Even in this rectilinear line detection itself, if the scanned form is inclined (skewed), the black frame line is thin or the frame line becomes blurred due to the sensitivity of scanners or noise. As a result, all black rectilinear lines may not be properly detected. In such a case, there is a disadvantage that scanning must be performed again by carefully overwriting the lines with thin printing with a pencil or pen which can be sensed by the scanner, adjusting sensitivity of the scanners, or carefully setting the form so that no skew occurs. In addition, since the detection of black rectilinear lines is a prerequisite, when it is intended to apply this program to the frame of a dropout form printed in color which is not sensed by the OCR scanner, there also arises a disadvantage in that all frames to be detected must be overwritten with a pen or pencil to be captured by the scanner.
The field definition method in the conventional character recognition program separately performs the field definitions and the detection of rectilinear lines. Since all black vertical and horizontal lines presented in the form image captured by the scanner are automatically detected whether or not each graphic (object) is required to be detected, unnecessary graphics detection processing is performed which decreases processing speed. In addition, in the automatic detection, it is impossible to distinguish objects other than the character frames such as page marks and position correction marks from the character frames.
In addition, in the above-mentioned second method, when a small display is used or when setting is performed for a small character frame, since dragging is not an easy operation for everyone, there is a possibility that an entire character frame intended to be set cannot be included in a rectangle formed by point-and-drag by the operator, or that another character frame will be included. Thus, some skill may be necessary for the operation of the pointer. Therefore, an approach is needed in which the operator can more easily specify fields and perform the operation more quickly.
On the other hand, the conventional character recognition programs use information of attributes of character fields for recognition accuracy up and some other objects. The information on the field attributes include information in determining whether an image-cut only is acquired or recognition is executed, or those on character type. Here, "an image-cut only" means a field only for acquiring an image without character recognition. On the other hand, "execution of recognition" means a field to which character recognition is actually applied. In addition, the "character type" includes information on selection of "hand writing" or "print," on selection of "upper case" or "lower case," or setting of a "symbol," "numeral," "katakana," "hiragana," "alphabet," or "kanji."
Since setting of the field attributes prevents "0" in a numeric entry from being erroneously recognized as "O" of an alphabetic entry, and the number of sets to be compared is reduced, there is an advantage that recognition can be attained at a high speed. Since there are characters which are difficult to distinguish such as the numeral "0" and the letter "O" particularly in the recognition of hand written characters, this information is essential and it is necessary to perform the above definition for each type of form. If a definition of such attributes and detection of rectilinear lines can be attained in a series of operations, the operator can smoothly and quickly define the form.
Other techniques relating to the present invention include Published Unexamined Japanese Patent Application (PUPA) Nos. 7-160811, 7-225809, and 7-57049. However, PUPA No. 7-160811 relates to a technique in which modification is performed by selecting a region of displayed binary image information with a pointing device and expanding or reducing the region. PUPA No. 7-225809 relates to a technique in which a frame to be read is generated by indicating one point at the upper left corner with indicating means. PUPA No. 7-57049 relates to a technique in which the order for reading regions such as character, table and photo regions is changed by using a mouse or the like. Therefore, they cannot recognize position information of parts of quadrilateral frames contained in an input bitmap image quickly and in a high speed.
An object of the present invention is to provide an image processing system with a simple user interface and capable of operating at a high speed. In addition, according to one aspect of the present invention, it is intended to provide a character recognition processing system which can accommodate slight skew, improper setting of density (sensitivity) of a scanner, or blur of lines forming the frame due to noise in defining a form for OCR. Furthermore, according to another aspect of the present invention, it is intended to provide a character recognition processing system which can easily and semi-automatically define a page mark or a position correction mark and can easily define a dropout form.